Method for filtering a liquid

ABSTRACT

An oil filter assembly is disclosed for a machine, such as an internal combustion engine, that has an oil output port and an oil input port. A mounting plate is fixed with an outer enclosure. The mounting plate is further adapted to conduct oil from the machine into a peripheral portion of the outer enclosure, and then returning oil from a central portion of the outer enclosure back to the machine. Oil may pass from the peripheral portion to the central portion through a primary filter having a first porosity. A pressure-actuated valve is fixed fluidly between the portions of the outer enclosure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. application Ser.No. 13/481,709, filed May 25, 2012, now allowed, which is a divisionalapplication of U.S. application Ser. No. 12/406,878, filed Mar. 18,2009, now U.S. Pat. No. 8,187,458 issued on May 29, 2012, thedisclosures of which are hereby incorporated by reference in theirentirety for all purposes.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT

Not Applicable.

NOTICE OF COPYRIGHTS AND TRADE DRESS

A portion of the disclosure of this patent document contains materialwhich is subject to copyright protection. This patent document may showand/or describe matter which is or may become trade dress of the owner.The copyright and trade dress owner has no objection to the facsimilereproduction by any one of the patent disclosure as it appears in thePatent and Trademark Office patent files or records, but otherwisereserves all copyright and trade dress rights whatsoever.

FIELD OF THE INVENTION

This invention relates to filters, and more particularly to an improvedengine oil filter assembly.

DISCUSSION OF RELATED ART

Conventional oil filters for vehicle engines, such as automotiveinternal combustion engines, typically include a filter media and abypass valve that is actuated when the filter media becomes dirty andsubstantially plugged. For example, U.S. Pat. No. 5,066,391 to Faria onNov. 19, 1991 teaches such a device. One drawback with such devices isthat once the bypass valve is opened, particulate debris that wouldnormally be captured by the filter media is able to traverse the valveand re-enter the engine, leading to engine wear and eventual damage.However, forcing oil through a filter media has the drawback that oncethe filter media becomes plugged with particulate matter, not enough oilcan get through the filter to effectively cool the engine, leading tomuch sooner engine damage than if even dirty oil were allowed tocirculate. Another drawback of such devices is that particulate matter,once captured on a leading side of the filter media, can be dislodgedfrom the filter to return back to the engine once the bypass valveopens, since flow of the oil at that point changes from through thefilter media to across the filter media.

Other such filters are disclosed in U.S. Pat. No. 5,711,872 to Jones etal. on Jan. 27, 1998; U.S. Pat. No. 6,068,762 to Stone et al. on May 20,2000; U.S. Pat. No. 6,540,914 to Smith on Apr. 1, 2003; and U.S. Pat.No. 7,413,089 to Tidwell on Aug. 19, 2008. These devices suffer many ofthe same drawbacks as the Faria device.

Therefore, there is a need for a device that overcomes the drawbacksassociated with the prior art. Such a needed filter device would open abypass valve once the primary filter becomes plugged, but wouldadditionally filter the oil through a secondary more porous filter. Sucha needed filter would be easily cleaned to restore the effectiveness ofthe primary filter, and would be made of durable materials that wouldlast potentially longer than the machine to which it is fixed. Such adevice would further provide for cooling of the oil as it passestherethrough. The present invention accomplishes these objectives.

SUMMARY OF THE INVENTION

The present device is an oil filter assembly for a machine, such as aninternal combustion engine, that has an oil output port and an oil inputport. A mounting plate is fixed with an outer enclosure, such as with afirst set of cooperative threads, and is adapted for securing to themachine, such as with a second set of cooperative threads. The mountingplate is further adapted to conduct oil from the oil output port of themachine into a peripheral portion of the outer enclosure, and thenreturning oil from a central portion of the outer enclosure into the oilinput port of the machine.

A primary filter has a first porosity. Oil may pass through the primaryfilter to move from the peripheral portion to the central portion of theouter enclosure. A pressure-actuated valve is fixed fluidly between theperipheral portion and central portion of the outer enclosure. Oil maypass through the pressure-actuated valve only when an oil pressuredifferential between the peripheral portion and the central portion ofthe outer enclosure exceeds a predetermined threshold pressure, such aswhen the primary filter 50 becomes dirty. A secondary filter has asecond porosity greater than the first porosity, and is fixed fluidlybetween the pressure-actuated valve and the central portion of the outerenclosure.

As such, as oil traverses the oil filter assembly from the oil outputport of the machine to the oil input port of the machine, the oil mustpass through either the primary filter or, if the predetermined pressurethreshold P has been reached, either the primary filter or the secondaryfilter. When the primary filter becomes dirty, such as after apredetermined number of machine operating hours, for example, the oilfilter assembly may be disassembled and each component washed,preferably in a standard dishwasher or the like.

The present invention is a filter device that opens the bypasspressure-actuated valve once primary filter becomes plugged, butadditionally continues to filter the oil through the secondary moreporous filter. The present device is easily cleaned, such as in aconventional household dishwasher, to restore the effectiveness of theprimary filter, and is made of durable materials that can lastpotentially longer than the vehicle or machine to which it is installed.The present invention further cools the oil as it passes therethrough.Other features and advantages of the present invention will becomeapparent from the following more detailed description, taken inconjunction with the accompanying drawings, which illustrate, by way ofexample, the principles of the invention.

DESCRIPTION OF THE DRAWINGS

FIG. 1A is a cross-sectional view of the invention, illustrating a flowof oil through a primary filter within an outer enclosure of theinvention;

FIG. 1B is a cross-sectional view of the invention of FIG. 1A, wherein apressure differential between peripheral and central portions of theenclosure exceeds a threshold pressure to open a pressure-actuated valveof the invention, illustrating a flow of oil through both the primaryfilter and a secondary filter;

FIG. 2 is a side elevational view of a mounting plate of the invention;

FIG. 3 is a cross-sectional view of the mounting plate, taken generallyalong lines 3-3 of FIG. 4;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view of the invention;

FIG. 7 is an exploded perspective view of a secondary filter assembly ofthe invention;

FIG. 8 is a partially exploded view of the primary filter of theinvention; and

FIG. 9 is a pressure diagram showing a pressure within the enclosureover time, as the primary and secondary filters become dirty andclogged.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Illustrative embodiments of the invention are described below. Thefollowing explanation provides specific details for a thoroughunderstanding of and enabling description for to these embodiments. Oneskilled in the art will understand that the invention may be practicedwithout such details. In other instances, well-known structures andfunctions have not been shown or described in detail to avoidunnecessarily obscuring the description of the embodiments.

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,” and thelike are to be construed in an inclusive sense as opposed to anexclusive or exhaustive sense; that is to say, in the sense of“including, but not limited to.” Words using the singular or pluralnumber also include the plural or singular number respectively.Additionally, the words “herein,” “above,” “below” and words of similarimport, when used in this application, shall refer to this applicationas a whole and not to any particular portions of this application. Whenthe claims use the word “or” in reference to a list of two or moreitems, that word covers all of the following interpretations of theword: any of the items in the list, all of the items in the list and anycombination of the items in the list. The words “oil” or “oils,” whenused the description and the claims, shall refer to any liquid to befiltered, and are not necessarily limited to engine or machinelubricating fluids.

FIGS. 1A and 1B illustrate an oil filter assembly 10 for a machine 20,such as an internal combustion engine, that has an oil output port 21and an oil input port 22. A mounting plate 30 (FIGS. 2-5) is fixed withan outer enclosure 40, such as with a first set of cooperative threads90, and is adapted for securing to the machine 20, such as with a secondset of cooperative threads 100. The mounting plate 30 is further adaptedto conduct oil from the oil output port 21 of the machine 20 into aperipheral portion 48 of the outer enclosure 40 (FIG. 1A), and thenreturning oil from a central portion 45 (FIGS. 1A and 1B) of the outerenclosure 40 into the oil input port 22 of the machine 20. In oneembodiment, the enclosure 40 includes a plurality of cooling fins 150(FIG. 6) protruding radially therefrom. Further, the mounting plate 30may include several viton seals 99 (FIGS. 3-5), as is known in the art.

A primary filter 50 has a first porosity P₁, preferably less than 15microns. In one embodiment, the first porosity P1 is about 5 microns.Oil may pass through the primary filter 50 to move from the peripheralportion 48 to the central portion 45 of the outer enclosure 40. In oneembodiment, the primary filter 50 is sandwiched between two semi-rigidprotective grids 80 (FIG. 8) each made from a durable, dishwasher safematerial such as a metallic stainless mesh material, or the like. Suchsemi-rigid protective grids 80 help maintain the shape of the primaryfilter 50 while in use within the enclosure 40.

A pressure-actuated valve 70 is fixed fluidly between the peripheralportion 48 and central portion 45 of the outer enclosure 40. Oil maypass through the pressure-actuated valve 70 only when an oil pressuredifferential between the peripheral portion 48 and the central portion45 of the outer enclosure 40 exceeds a predetermined threshold pressureP_(t), such as when the primary filter 50 becomes dirty or clogged withdebris (FIG. 9). In embodiment the pressure-actuated valve 70 is a ballvalve that includes a ball 110 biased in a closed position 130 with aspring 120. The ball 110 may be urged into an open position 140 when thethreshold pressure P_(t) is exceeded. Preferably the ball 110 and othercomponents are durable and easily cleaned, such as titanium or tungsten.

A secondary filter 60 has a second porosity P₂, P₂ being greater thanP₁, and is fixed fluidly between the pressure-actuated valve 70 and thecentral portion 45 of the outer enclosure 40 (FIGS. 1B and 7).Preferably P2 is greater than about 15 microns, and in one embodiment isabout 25 microns.

In one embodiment, the primary filter 50 is substantially cylindricaland includes an end cap 160 (FIG. 8) that has a threaded aperture 165for mounting thereto a secondary filter assembly 170 (FIG. 7). Thesecondary filter assembly 170 includes a secondary filter housing 180that at least partially encloses the secondary filter 60 and fixes thesecondary filter 60 and the pressure-actuated valve 70 to the end cap160 with a ball seat and seal plate 190.

As such, as oil traverses the oil filter assembly 10 from the oil outputport 21 of the machine 20 to the oil input port 22 of the machine 20,the oil must pass through either the primary filter 50 or, if thepredetermined pressure threshold P_(t) has been reached, either theprimary filter 50 or the secondary filter 60. With the cooling fins 150of the enclosure 40, the oil is cooled as it passes through theperipheral portion 48 of the enclosure 40. When the primary filter 50becomes dirty, such as after a predetermined number of machine operatinghours, for example, the oil filter assembly 10 may be disassembled andeach component washed, preferably in a standard dishwasher or the like.As such, the primary and secondary filters 50, 60 are preferably madefrom a material that is dishwasher safe, corrosion resistant, anddurable, such as a titanium mesh, a metallic stainless mesh, a hybridceramic material, or the like.

While a particular form of the invention has been illustrated anddescribed, it will be apparent that various modifications can be madewithout departing from the spirit and scope of the invention. Forexample, a ball valve is illustrated as the pressure-actuated valve 70in the drawings, but a pin-valve or other equivalent pressure-actuatedvalve 70 may also be used. Accordingly, it is not intended that theinvention be limited, except as by the appended claims.

The teachings provided herein can be applied to other systems, notnecessarily the system described herein. The elements and acts of thevarious embodiments described above can be combined to provide furtherembodiments. All of the above patents and applications and otherreferences, including any that may be listed in accompanying filingpapers, are incorporated herein by reference. Aspects of the inventioncan be modified, if necessary, to employ the systems, functions, andconcepts of the various references described above to provide yetfurther embodiments of the invention.

These and other changes can be made to the invention in light of theabove Detailed Description. While the above description details certainembodiments of the invention and describes the best mode contemplated,no matter how detailed the above appears in text, the invention can bepracticed in many ways. Details of the system may vary considerably inits implementation details, while still being encompassed by theinvention disclosed herein.

Particular terminology used when describing certain features or aspectsof the invention should not be taken to imply that the terminology isbeing redefined herein to be restricted to any specific characteristics,features, or aspects of the invention with which that terminology isassociated. In general, the terms used in the following claims shouldnot be construed to limit the invention to the specific embodimentsdisclosed in the specification, unless the above Detailed Descriptionsection explicitly defines such terms. Accordingly, the actual scope ofthe invention encompasses not only the disclosed embodiments, but alsoall equivalent ways of practicing or implementing the invention.

The above detailed description of the embodiments of the invention isnot intended to be exhaustive or to limit the invention to the preciseform disclosed above or to the particular field of usage mentioned inthis disclosure. While specific embodiments of, and examples for, theinvention are described above for illustrative purposes, variousequivalent modifications are possible within the scope of the invention,as those skilled in the relevant art will recognize. Also, the teachingsof the invention provided herein can be applied to other systems, notnecessarily the system described above. The elements and acts of thevarious embodiments described above can be combined to provide furtherembodiments.

All of the above patents and applications and other references,including any that may be listed in accompanying filing papers, areincorporated herein by reference. Aspects of the invention can bemodified, if necessary, to employ the systems, functions, and conceptsof the various references described above to provide yet furtherembodiments of the invention.

Changes can be made to the invention in light of the above “DetailedDescription.” While the above description details certain embodiments ofthe invention and describes the best mode contemplated, no matter howdetailed the above appears in text, the invention can be practiced inmany ways. Therefore, implementation details may vary considerably whilestill being encompassed by the invention disclosed herein. As notedabove, particular terminology used when describing certain features oraspects of the invention should not be taken to imply that theterminology is being redefined herein to be restricted to any specificcharacteristics, features, or aspects of the invention with which thatterminology is associated.

In general, the terms used in the following claims should not beconstrued to limit the invention to the specific embodiments disclosedin the specification, unless the above Detailed Description sectionexplicitly defines such terms. Accordingly, the actual scope of theinvention encompasses not only the disclosed embodiments, but also allequivalent ways of practicing or implementing the invention under theclaims.

While certain aspects of the invention are presented below in certainclaim forms, the inventor contemplates the various aspects of theinvention in any number of claim forms. Accordingly, the inventorreserves the right to add additional claims after filing the applicationto pursue such additional claim forms for other aspects of theinvention.

What is claimed is:
 1. A method for filtering a liquid, comprising:providing a filter assembly comprising (i) an outer enclosure comprisinga peripheral portion and a central portion; (ii) a primary filterdisposed within the outer enclosure such that a liquid in the peripheralportion passes across the primary filter into the central portion; (iii)a pressure-actuated valve disposed between the peripheral and centralportions of the outer enclosure, said valve movable into an openposition in response to a pressure differential; (iv) a secondary filterdisposed within the primary filter and between the pressure-actuatedvalve and the central portion of the outer enclosure; and (v) a mountingplate to which the outer enclosure is removably fixed, the mountingplate adapted to conduct the liquid from an outlet port of an attachedmachine into the peripheral portion of the outer enclosure via a taperedconduit.
 2. The method of claim 1, wherein the primary and secondaryfilters are each made from a titanium mesh.
 3. The method of claim 2,wherein the primary filter has a porosity of less than about 15 microns.4. The method of claim 2, wherein the secondary filter has a porosity ofgreater than about 15 microns.
 5. The method of claim 1, wherein themounting plate is fixed to the outer enclosure with a first set ofcooperative threads.
 6. The method of claim 1, further comprisingattaching the oil filter to the outlet port of a machine comprising aliquid to be filtered.
 7. The method of claim 6, wherein the mountingplate is secured to the machine with a second set of cooperativethreads.
 8. The method of claim 1, wherein the pressure-actuated valveincludes a ball valve biased in a closed position with a spring.
 9. Themethod of claim 1, wherein the outer enclosure further includes aplurality of cooling fins protruding radially therefrom.
 10. The methodof claim 1, wherein the primary filter is substantially cylindrical andincludes an end cap with a threaded aperture for mounting thereto asecondary filter assembly that includes a secondary filter housing thatat least partially encloses the secondary filter and fixes the secondaryfilter and the pressure-actuated valve to the end cap with a ball seatand seal plate.
 11. The method of claim 7, further comprising filteringthe liquid until the primary filter is dirty.
 12. The method of claim11, further comprising removing the primary filter from liquidcommunication with the machine and cleaning the filter.